Last year, a team of biomedical engineering students was asked to consider a real-life problem. Is there a safer, less intrusive way to close the chest cavity after surgery than the traditional use of heavy steel wire?
After nine months of work, the group’s conclusion was a resounding yes. The result was the design and production of a new chest-closure device that holds much commercial potential and could revolutionize the more than 700,000 open-chest surgeries each year.
The 11-member team, headed by Chris Weier ’06 and Neha Malhotra, now a senior, was awarded first place in the university’s Biomedical Engineering Design Day competition last May. A New York–based company, Surgical Transformations LLC, headed by Whiting School grad Malcolm Lloyd ’94, was a corporate sponsor for the project, one of many tackled in the course Biomedical Engineering Design Teams. Lloyd, who attended medical school himself, proposed the idea of a new chest-closure system because he knew the need was great among surgeons. “We gave the students a list of factors to consider,” he says, “and they were successful in solving every one.”
Currently, cardiothoracic surgeons around the world close chest cavities in a half-century-old technique that involves sewing the breastbone back together with a sharp needle and heavy-duty wire. There are problems with this approach. For one, the wire must remain in the patient’s body indefinitely, making metal detectors an ongoing problem. In addition, the closure procedures require tremendous physical effort on the part of surgeons, often following long, exhausting surgeries.
“We decided the best approach was a device that used some type of cable ties, made of a biodegradable material,” says Malhotra. The team leaders divided the group into separate subcommittees responsible for the device design, the testing, and the selection of material.
Before starting, the students talked with Hopkins cardiothoracic surgeons and examined a breastbone in a human cadaver lab. “We were trying to look at it from a surgeon’s point of view,” says Weier, who now works as a research assistant in a biomedical engineering lab at Hopkins. “We needed to cut down on the time and effort exerted after what could be a four- or five-hour surgery and we wanted to make it safer for the patients.”
The project presented challenges. The students needed a device that could adapt to anatomical differences of patients. They wanted a material that had the right amount of flexibility, but was biodegradable. (It takes roughly two months for a breastbone to completely fuse.) And the solution couldn’t be complicated. “We wanted something with a simple, one- or two-step process,” says Alex King, one of the freshmen on the team.
In the end, the group came up with a medical device that looks like a stapler. But it ratchets the breastbone together, using biodegradable plastic ties rather than metal staples. The ratchet motion cuts down on the energy and effort needed by surgeons. And the team suggested one biodegradable material, poly caprolactone, as a possibility. Then, they spent about $1,000 to have a prototype built. “When it arrived in April, it was like Christmas,” says King.
Surgical Transformations has obtained a provisional patent on behalf of the students for the device. Company exec Lloyd says he’s now exploring the commercial potential of the product. “We’re very optimistic,” he says.